Severe combined adrenal and gonadal deficiency caused by novel mutations in the cholesterol side chain cleavage enzyme, P450scc.

CONTEXT: Mitochondrial cytochrome P450scc converts cholesterol to pregnenolone in all steroidogenic tissues. Although progesterone production from the fetally-derived placenta is necessary to maintain pregnancy to term, four patients with mutations in the gene encoding P450scc (CYP11A1), have been described, one in a 46,XX female and three in underandrogenized 46,XY individuals, all with primary adrenal failure. OBJECTIVE: Our aim was to determine whether P450scc mutations might be found in other children and to explore genotype/phenotype correlations. METHODS AND PATIENTS: We performed mutational analysis of CYP11A1 in individuals with 46,XY disorders of sex development and primary adrenal failure, followed by functional studies of P450scc activity and of P450scc RNA splicing. RESULTS: Among nine 46,XY infants with adrenal failure and disordered sexual differentiation, two infants had compound heterozygous mutations in CYP11A1. One patient harbored the novel P450scc missense mutations L141W and V415E, which retained 38 and 0% activity, respectively. The other carried a CYP11A1 frameshift mutation c835delA (0% activity) and a splice site mutation [IVS3+(2-3)insT] that prevented correct splicing of P450scc mRNA. CONCLUSIONS: P450scc deficiency is a recently recognized disorder that may be more frequent than originally thought. The phenotypic spectrum ranges from severe loss-of-function mutations associated with prematurity, complete underandrogenization, and severe, early-onset adrenal failure, to partial deficiencies found in children born at term with clitoromegaly and later-onset adrenal failure. In contradistinction to congenital lipoid adrenal hyperplasia caused by steroidogenic acute regulatory protein mutations, adrenal hyperplasia has not been reported in any of the six patients with P450scc deficiency.

Transient neonatal diabetes mellitus, type 4, type 1 diabetes mellitus, or MODY: which disease is it, anyway?

A 30year-old Hispanic male who presented with transient neonatal diabetes mellitus at 4 months has been intensively studied with 12 islet-cell secretagogues from 4 months to 24 years. He was both ICA- and GAD-65-negative, but at 28 years was diagnosed with hypothyroidism due to positive thyroperoxidase antibodies. The course of his disease(s) and the various presentations of hyperglycemia are documented and illustrated by the responses in islet cell hormone secretion, namely, insulin, glucagon, and C-peptide. Insulin secretion gradually fell over 24 years, glucagon secretion persisted from infancy to 24 years but was only minimal during i.v. glucose at 24 years, and C-peptide secretion remained normal, although modest, throughout the 24 years. These data suggest that, despite changing presentations of diabetes mellitus over time, the islets continued to process proinsulin, although the patient required insulin therapy.

Congenital adrenal hypoplasia and male pseudohermaphroditism due to DAX1 mutation, SF1 mutation or neither: a patient report.

A 15 year-old African American phenotypic female with congenital adrenal hypoplasia and intra-abdominal testes is described; she received cortisone acetate, 9alpha-Florinef, Premarin and Provera for maintenance therapy. Evaluation for DAX1, SF1 mutations using Southern blotting, PCR, PCR amplification, coding sequences, and splice site analyses have not detected any genetic abnormalities. While only 30% of the reported DAX1 mutation defects have been identified by a variety of genetic laboratory techniques, it remains probable that this unusual patient has either a DAX1 or SF1 mutation defect. A Wnt-4 defect was not evaluated.

Familial dysalbuminemic hyperthyroxinemia: a rare example of albumin polymorphism and its rapid molecular diagnosis.

Familial dysalbuminemic hyperthyroxinemia (FDH) is the most common cause of euthyroid hyperthyroxinemia, although a rare example of albumin polymorphism. FDH is inherited in an autosomal dominant manner and is characterized by enhanced binding of thyroxine to a mutant form of albumin, probably at Site 1, subdomain 11A. Previous laboratory tests of FDH have been cumbersome, rarely available, and required demonstration of anti-albumin precipitable T4, isoelectric focusing of serum for albumin in presence of labeled T4 and, occasionally, comparison of the concentrations of metabolites of T4 that have different binding affinities to the abnormal albumin. Recent studies have shown that the same mutation in the albumin gene that results in FDH has been found in 13 unrelated families. A G-->A transition in codon 218 of the albumin gene resulted in the replacement of arginine with histidine. An intragenic Sac-1 polymorphic site was found in association with the specific FDH mutation, suggesting a founder effect. FDH in our Hispanic family was confirmed by isoelectric focusing of serum. Results of thyroid function tests in our affected patients were typical for the phenotype: high total T4 and normal total T3. Genomic DNA was amplified by PCR using a mismatched oligonucleotide primer that produced a unique restriction site (Dra III) only if the DNA sample contained the mutation in codon 218: CGC (Arg) to CAC (His). In affected individuals of this family expression of the FDH phenotype was associated with the presence of His218 in one of the two alleles. Analysis linking the FDH mutation to the Sac-1 polymorphism in this family was not informative. DNA analysis is a rapid and simple method to diagnose FDH in individuals with euthyroid hyperthyroxinemia.

Monozygotic twins with congenital adrenal hyperplasia: long-term endocrine evaluation and gene analysis.

Monozygotic female twins with congenital adrenal hyperplasia due to 21-hydroxylase deficiency are described and evaluated over the first 6 years of life. Despite appropriate steroids, NaCl, and fludrocortisone therapies, there was significant fluctuation in the suppression of adrenal steroid secretion. Advanced bone maturation in both was noted. For the first time, molecular genetic analysis was performed and documented that the twins were compound heterozygotes for two different mutations: the maternal allele carried the 8-bp deletion mutation, whereas the paternal allele carried the 1172N missense mutation. Parental DNA samples confirmed that the mutations were on different alleles.